The present invention relates to rolling mills for continuously rolling round elongated rods into wire, and more particularly, to finishing blocks of the torsionless type for finishing the rolled wire.
A torsionless finishing block generally comprises eight or ten rolling stands, with each stand being shifted 90.degree. with respect to the next succeeding stand. The rollers of each stand are normally mounted in a cantilevered fashion at the end of the roller shafts.
In such a finishing block, the rollers of the stands are driven by a common transmission device at rotational speeds which increase at a fixed ratio between successive stands in the downstream rolling direction. The speed ratio is selected in accordance with the range of cross-sectional sizes of wire or rods being produced. When an attempt is made to increase the range of wire sizes produced beyond the maximum for which the rolling mill was designed, it becomes extremely difficult, if not impossible, to produce larger strands of wire with the required shape and within the required dimensional tolerances using the same mill.
Rather, oversized wire rolled in a mill having a limited size range contains certain imperfections in terms of shape, such as beading and excess metal resulting from intermediate stands, and in terms of dimension. These imperfections, which are not correctable by the stands of the finishing blocks, result in lower grade wire or rejected wire which in turn results in expensive and unprofitable production. On the other hand, with conventional multi-line rolling mills, it is not possible to produce wire with tolerances more restrictive than those for which the mill was designed without expensive modifications of existing equipment.